Luther stieringer



L. S.TIERINGER.

SAFETY GATGH FOR ELECTRIC LIGHT CIRCUITS No. 281,576.

Patented, July 17, 1883.

Fzig. 1,

UNITED STATES PATENT OFFICE.

LUTHER STIERINGER, on NEW YORK, N. Y., ASSIGNOR TO THE EDISON ELECTRIC LIGHT COMPANY, OF SAME PLACE.

SAFETY-CATCH FOR ELECTRIC-LIGHT CIRCUITS.

SPECIFICATION forming part of Letters Patent No. 281,576, dated July 17, 1883.

Application filed March 16, 1883. (No model.)

To aZZ whmn it may concern:

Be it known that I, LUTHER STIERINGER, of New York city, in the county and State of New York, have invented a certain new and useful Improvement in Safety-Catches for Electric- Light Circuits, of which the following is a specification.

Heretofore in the use of lead or other wire fusible at a low heat, for the safety-catches 0f electriclight circuits, it has been usual to secure the wire in circuit by clamping it directly beneath the heads of binding-screws. I have found that a good and lasting contact cannot be made in this way between the lead wire and binding-screws, and that many safety-catches are destroyed by the heating of the contacts without an abnormal flow of current, against which they are designed to guard. This poor contact is due to the small binding-surface of the screws on the wire, to the ready oxidation of the lead, and to the fact that the screws cannot be forced down hard upon the lead by reason of its lack of elasticity, its softness, and the danger of cuttingoff the wire by the heads of the screws; hence the screws soon work loose, and the oxidation and heating of the contacts and the destruction of the safety-catches are the inevitable results.

The object, therefore, of my invention is to overcome this difficulty, which I do by soldering or fusing the lead or other safetycatch wire to terminals of other and harder and elastic metal, upon which the binding-screws bear. Copper plates are preferred, having holes or notches through which the screws pass.

The invention further relates to the construction of a fusible safety catch, designed more especially to carry heavy or main-line currents, which will not be subject to the disadvantages of safety-catches breaking the circuit at one point only, resulting from the 111- tense heat centered at that point, and will also permit of a ready change in the carrying capacity of the safety-catch; and the invention also includes means for preventing the cutting or breaking of the safetycatches when the binding-screws are forced down upon the end plates, for permitting the replacement of the safetycatches without removing the bindingscrews, and for preventing the danger from firing or carbonizing the parts supporting and surrounding the safetycatches, all as more fully hereinafter explained.

In the accompanying drawings, forming a 1 part hereof, Figurel is a top view of the safetycatch for heavy or mainline currents; Fig. 2, a vertical section of the same; Fig. 3, a separate perspective view of one end of a safetycatch placed 011 its support, but not secured; Fig. 4, atop view of one end of a safety-catch; Fig. 5, a perspective view of a form of safetycatch having one fusible link, and Fig. 6 a perspective view of the protecting-cover for the same.

Like letters denote corresponding parts in all the figures.

A is the fusible safety-catch link, composed of lead or other suitable metal or alloy fusible at a low heat. It is soldered or fused at its ends to plates 13 of some hard and elastic metal, for which purpose copper is preferred. The plates 13 are provided with slots 1), extending inwardly from their ends, and are held by bindingscrews a. The binding-screws enter supporting metallic plates or blocks 0 O, which are mounted upon a non-combustible and noncarbonizable insulating -base, D, capable of withstanding high heat, such as earthenware or glass, or any suitable composition. The binding-screws may have slotted heads; or they may be thumb-screws. The slots in the end plates, B, permit the replacement of the safetycatch by simply loosening the screws a, and without removing them from the plates or blocks 0 O. The screws can be set down hard upon the copper end platesfmaking a good and lasting Contact therewith, having a large surface and such low resistance that there will be no danger of heating or oxidizing.

The metallic plates or blocks 0 G are provided with angular depressions c, and the plates B are made of the same shape, so that such plates cannot turn and cut the safetycatch link when the binding-screws are forced down upon them. It is evident that the locking of the supporting-blocks and end plates, to prevent the turning of such end plates, could be accomplished in a number of ways differing in specific construction from that shown.

For a main-line safety catch, or one for heavy currents, the metallic supporting blocks or plates 0 O are made of sufficient length to carry several fusible safety-catch links, which extend from one to the other of the blocks, as shown in Fig. 1, and these blocks have central extensions, E, upon which clamp-plates E are secured for clamping the circuit-wires F. In this construction the fusible safety-catch links have a multiple-arc relation to each other, and more or less of such links can be used, as re quired, for the number of lamps to be carried, the number of lamps which each link is capable of carrying being ascertained and preferably stamped on one of the end plates. When this multiple safety-catch is destroyed, it does not go all at once, but the weakest link is first fused and the others in succession.

For a sin gle-link safety -catch the form shown in Fig. 5 may be used, the circuit-wires being secured to extensions of C- C. A cover, G, of the same material as the base D, may be used, and such a cover may also be employed with the multiple safety-catch.

\Vhat I claim is 1. A fusible safety-catch link having end plates of harder metal, to which the fusible metal is fused or soldered, substantially as set forth.

2. A fusible safety-catch link having end plates of harder metal fused or soldered thereto, in combination with metallic supports and binding-screws clamping the end plates, substantially as set forth.

3. A fusible safety-catch link having end plates of harder metal fused or soldered thereto and secured by binding-screws, in combination with means for locking the end plates against turning when the binding-screws are turned, substantially as set forth.

4. A fusible safety-catch link having end plates of harder metal fused or soldered thereto, such end plates being provided wit-h slots for receiving bindingscrews, substantially as set forth.

5. A fusible safety-catch secured to metallic supports mounted upon a base of noncombustible and non-carbonizable insulating material, substantially as set forth.

6. The combination of a fusible safety-catch, end plates of harder metal, metallic supports for the end plates, binding-screws, and a base of non-combustible and non-earbonizable insulating material, substantially as set forth.

7. The combination, with. a conductor forming one side of an electric circuit, of two or more separate and independently-removable safety-catch links interpolated in such eonductor in multiple-arc relation to each other, substantially as set forth.

8. The combination, with metallic plates or blocks and circuit-wires connected therewith, of two or more separate fusible safety-catch links connecting such metallic plates or blocks, substantially as set forth.

9. The combination, with metallic plates or blocks and the ci1.'cuit-wires connected there with, of two or more fusible satetycatch links connecting such metallic plates or blocks, such fusible links having end plates of harder metal, and being secured by bimling-sercws, substantially as set forth.

This specification signed and witnessed this 19th day of February, 1883.

LUTHER STIERING ER.

lVitnesses:

lVM. H. MEADoweRom, H. \V. Sunny. 

